Sept 4 2018; New York, NY, USA;
Rafael Nadal of Spain hits to Dominic Thiem of Austria in a quarterfinal match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Robert Deutsch-USA TODAY Sports

Foto: Robert Deutsch

Sep 4, 2018; New York, NY, USA; Rafael Nadal of Spain reacts after a point against Dominic Thiem of Austria in a quarter-final match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Danielle Parhizkaran-USA TODAY SPORTS

Foto: Danielle Parhizkaran

Sept 4 2018; New York, NY, USA;
Rafael Nadal of Spain serves to Dominic Thiem of Austria in a quarterfinal match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Robert Deutsch-USA TODAY Sports

Foto: Robert Deutsch

Sep 4, 2018; New York, NY, USA; Rafael Nadal of Spain hits to Dominic Thiem of Austria in a quarter-final match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Danielle Parhizkaran-USA TODAY SPORTS

Foto: Danielle Parhizkaran

Sep 4, 2018; New York, NY, USA; Juan Martin Del Potro of Argentina celebrates match point against John Isner of the United States in a quarter-final match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Jerry Lai-USA TODAY Sports

Foto: Jerry Lai

Sep 4, 2018; New York, NY, USA; Juan Martin Del Potro of Argentina (left) greets John Isner of the United States (right) after a quarter-final match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Jerry Lai-USA TODAY Sports

Foto: Jerry Lai

Sep 4, 2018; New York, NY, USA; Juan Martn Del Potro of Argentina hits a volley against John Isner of the United States (not pictured) in a quarter-final match on day nine of the 2018 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Geoff Burke-USA TODAY Sports